<h2><SPAN name="CHAPTER_III" id="CHAPTER_III"></SPAN>CHAPTER III.</h2>
<h3>HISTORY OF MAGNETISM.</h3>
<p>It is said that the word magnetism is derived
from the name of a Greek shepherd,
called Magnes, who once observed on Mount
Ida the attractive properties of loadstone when
applied to his iron shepherd's crook. It is
more likely that the name came from Magnesia,
a country in Lydia, where it was first
discovered. It was also called Lapis Heracleus.
Heraclea was the capital of Magnesia.
Loadstone is a magnetic ore or oxide of iron
found in the natural state, and has at some
time by natural processes been rendered magnetic—that
is, given the power of attracting
iron, and, when suspended, of pointing to the
North and South Poles. The power of the
natural magnet was known at a very early age
in the history of man. It was referred to by
Homer, Pythagoras, and Aristotle. Pliny also
speaks of it, and refers to one Dinocares, who
recommended to Ptolemy Philadelphus to build
a temple at Alexandria and suspend in its
vault a statue of the queen by the attractive
power of "loadstones." There is also mention<span class="pagenum"><SPAN name="Page_21" id="Page_21"></SPAN></span>
of a statue being suspended in like manner
in the temple of Serapis, Alexandria.</p>
<p>It is claimed that the Chinese knew of and
used the magnetic needle in the earliest times
and that travelers by land employed this
needle suspended by a string to guide them in
their journeys across the country a thousand
years before Christ. Notwithstanding the
claims of the Chinese and Arabians to the discovery
of the use of the magnetic needle,
modern authors question whether the ancients
were familiar with any artificial construction
of a magnetic needle, however much they may
have studied and used the loadstones. No
doubt the loadstone in its natural state was
used by mariners to steer their ships by, long
before its artificial counterpart was invented.
In a history of the discovery of Iceland, by Are
Frode, who was born in 1068, it is stated that
a mariner by name of Folke Gadenhalen sailed
from Norway in search of Iceland in the year
868, and that he carried with him three ravens
as guides, for he says, "in those times seamen
had no loadstones in the northern countries."
The magnetic needle as applied to the mariner's
compass was known in the eleventh century,
as proved by various authors. In an old
French poem, the manuscript of which still
exists, the mariner's compass is clearly mentioned.
The author was Guyot, of Provence,
who was alive in 1181.<span class="pagenum"><SPAN name="Page_22" id="Page_22"></SPAN></span></p>
<p>Like electricity, magnetism has had a long
history, but little use was made of it till
modern times beyond that of the mariner's
compass. It can readily be seen what an important
factor it was in the science of navigation.
Long after the discovery of the
compass needle there were many perplexing
problems arising, and all sorts of theories were
advanced to account for the various phenomena.
The variation of the needle was one
of these problems. It is said that Columbus
was the first to discover the variation of the
needle, as well as America. This is disputed,
however, as every man's pretensions usually
are. However this may be, Columbus had to
invent some plausible theory to account for
this variation to prevent a mutiny among his
crew. They were very superstitious and
thought that they were sailing into a new
world where the laws of nature were different
from those of Spain. One phenomenon that
disturbed Columbus was the dip of the needle.
As we move in a northerly direction a magnetic
needle dips, and it was the observation
of this phenomenon in different latitudes that
finally resulted in the invention of the dipping
needle. It is well known that one pole of a
magnetic needle points to the north and the
other to the south. In other words, what is
called the north pole of a needle points to
one of the magnetic poles of the earth which is<span class="pagenum"><SPAN name="Page_23" id="Page_23"></SPAN></span>
in the direction of the north pole, though not
the same as the geographical pole. A dipping
needle revolves on an axis so that it can point
to any declination. If we should construct
one that is perfectly balanced, so as to lie in
a perfectly horizontal direction before it is
magnetized, it will dip—in this latitude—downward
toward the north after magnetization.
If we keep moving northward it will
continue to dip downward till we come to the
true magnetic pole, when what is called the
north pole of the needle will point directly
downward. If we go back to the equator the
needle will lie horizontally again. We call the
end of the needle that points to the north the
north pole. It is really the south pole, because
unlike poles attract each other. If the
magnetic poles of the earth are at the north
and south geographical poles, the south pole
of the needle will point north. But it is less
confusing to call the end of the needle that
points north the north pole. The nomenclature
is purely arbitrary.</p>
<p>It was not until it was learned that magnets
could be made by electricity that they became
commercially important outside of their use
in navigation. The advent of electricity has
brought magnetism to the front as one of the
great factors in our modern civilization. And
we might say with equal force that the discovery
of magnetism has brought electricity<span class="pagenum"><SPAN name="Page_24" id="Page_24"></SPAN></span>
to the front. The truth is that they depend
upon each other. Electricity would be robbed
of a large part of its importance as a factor
in modern life if it were not for its relation to
magnetism. Even electric lighting would be
impossible, commercially, if it were not for the
part magnetism plays in the production of
electricity for this purpose. It could not be
successfully carried on with any battery but
the storage-battery, and the storage-battery is
dependent upon the dynamo, and the dynamo
is a magneto-electric machine. When we
come to analyze the relation between magnetism
and electricity we cannot separate them
without robbing each of a large part of its
usefulness. They are interdependent forces.</p>
<p>As in the case of electricity there have been
many theories regarding magnetism. One
philosopher in the old days accounts for the
variation of the compass-needle on the theory
that there are two globes, one revolving within
the other, and that any derangement of their
normal movements in relation to each other
affects the needle. Evidently there were
cranks in those days as well as now. Another
theory of magnetism was that there were two
fluids—a boreal and an austral—one developing
north polarity and the other south
polarity. In the next chapter the nature of
magnetism in the light of modern investigation
will be discussed.</p>
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